The present invention relates to fabric softener compositions, and more particularly to a fabric softener composition that comprises a blend of a methyl diethanol amine (MDEA) ester quaternary (quat) and a triethanol amine (TEA) ester quaternary (quat), wherein the MDEA ester quat has a high content of monoester. The fabric softener composition of the present invention provides improved softening performance as compared with either of the individual components alone. Moreover, the fabric softener composition of the present invention is capable of providing a high-solids formulation that forms stable dispersions that maintain long term stability.
In North America, methyl diethanol amine (MDEA) ester quats are generally used as softening agents in various fabric softener formulations. MDEA ester quats are typically made by reacting various fatty acids such as a tallow fatty acid with MDEA; MDEA, which is also known as 2,2xe2x80x2-methyliminodiethanol, has the basic structural formula (HOCH2CH2)2NCH3.
The MDEA ester quats are normally made so that the products contain low levels of monoester (on the order of about 4 to about 7% solids) for the fabric softener market because MDEA ester quats having a high monoester content are reported to be hard to formulate and they give thick gelatinuous formulations at high solids over 12%. Most formulations employed in the North American market are ultra products that are over 24% solids and even as high as 28% solids.
Triethanol amine (TEA) ester quats are the generic ester quats that are used in Europe, but TEA ester quats are not used much in the North America market because TEA ester quats do not soften well under Northern American washing conditions. The reasons for this is because of residual anionics remaining in the rinse cycle due to the single rinse cycles employed in typical North American top loading washing machines. Prior art TEA ester quats can only be formulated to about 18% solids due to their chemistry.
The raw materials used in making TEA quats arc lower in cost than MDEA ester quats and thus have a cost driver if TEA ester quats could be used in the production of fabric softener formulations in North American products.
Attempts have been made in the prior art to provide formulations in which MDEA and TEA ester quats are both present. In such formulations, a mixture of two different amines, i.e., MDEA/TEA, is first provided. The amine mixture is then esterified in the presence of a fatty acid and thereafter the esterification reaction product is quaternized. Such a formulation is disclosed, for example, in DE 196 42 038 C1 assigned to Henkel KGAA (hereinafter DE ""038).
Specifically, DE ""038 discloses quaternary esters that are obtained by esterifying MDEA/TEA mixtures (weight ratio=20-1:80-99) with fatty acids and then quaternizing the reaction product with an alkylating agent using known quaternization processes. The ester quats disclosed in DE ""038 are said to have a sufficiently low and storage stable viscosity which makes the ester quats highly suitable for use in cosmetics and brighteners.
In DE ""038, an esterification product of a partially hydrogenated C16-18 tallow fatty acid and a MDEA/TEA mixture is described for a fabric softener. In particular, DE ""038 discloses that the MDEA/TEA ratio on the order of 15% MDEA and 85% TEA makes a superior softener. Manufacturing quats in the manner disclosed in DE ""038 does not allow for the controlled production of MDEA having a high monoester content.
In view of the state of the prior art mentioned above, there is a need for providing a fabric softener composition that incorporates both MDEA and TEA ester quats into a single formulation in which the use of an amine pre-mixture, i.e., a mixture of MDEA and TEA which is formed prior to esterification and quaternization, is avoided.
The present invention relates to a fabric softener composition in which a blend of MDEA having a high monoester content and TEA ester quats is employed. Throughout the remaining portions of the application, the term xe2x80x9chigh mono alkyl MDEA ester quatxe2x80x9d is used to describe the MDEA having a high monoester content. It should be understood that the two terms are interchangeably used in the present application to describe a methyl diethanol amine ester quat having a mono alkyl ester quat level of about 10% or greater. It has been found by the present applicants that a formulated blend of a high mono alkyl MDEA ester quat, i.e., MDEA having a high monoester content, and a TEA ester quat provides improved softening performance that is better than that obtained with either of the individual components (standard low mono alkyl MDEA ester quats or standard TEA ester quats).
In addition, the applicants have determined that even though the individual ester quat products can be formulated to 12 to 18% solids, when the two ester quats are blended together, as in the present invention, the blend may have a solids content about 25% or higher. Moreover, the inventive blend of a high mono alkyl MDEA ester quat, i.e., MDEA having a high monoester content, and a TEA ester quat forms a stable dispersion that maintains long-term stability.
The fabric softener composition of the present invention has a definite synergism that enables the use of less expensive raw materials to provide improved softening results. The fabric softener composition of the present invention may further contain other quats blended with the initial blend of high mono alkyl MDEA ester quat, i.e., MDEA having a high monoester content, and TEA ester quat that provides even further softening improvements as well as stable formulations.
Normally formulations containing commercially available di tallow dimethyl ammonium chloride are known to thicken over time when they are formulated into a composition of high solids with TEA or MDEA ester quats. In the present invention, the high mono alkyl MDEA ester quat, i.e., MDEA having a high monoester content, and TEA ester quat compositional blend permits the formulation of a thermally stable high-solids product even when other conventional quats are formulated therein.
The fabric softener composition of the present invention, i.e., the blend of high mono alkyl MDEA ester quat (MDEA having a high monoester content) and TEA ester quat, can be dispersed in warm water to form high solids formulations that are stable under commercial conditions. The term xe2x80x9chigh solidsxe2x80x9d as used throughout the instant application denotes a solids content of about 20% or higher.
In broad terms, the present invention relates to a fabric softener composition that comprises a blend of from about 15 to about 65%, by weight of the total blend, of a triethanol amine ester quat and from about 35 to about 85%, by weight of the total blend, of a methyl diethanol amine ester quat, said methyl diethanol amine ester quat having a mono alkyl ester quat level of about 10% or greater. Throughout this application the term xe2x80x9chigh mono alkyl MDEA ester quatxe2x80x9d is used to describe the methyl diethanol amine ester quat having a mono alkyl ester (i.e., monoester) quat level of about 10% or greater.
The fabric softener composition of the present invention may contain more than one high mono alkyl MDEA ester quat and more than one TEA ester quat blended together. Other ingredients/components that are typically present in a fabric softener composition may or may not be present in the inventive TEA/MDEA ester quat blend. In some embodiments of the present invention, the blend consists essentially of the TEA ester quat and the MDEA ester quat; water can be used in conjunction with the TEA/MDEA blend since it would not materially affect the softening properties of the blend. Blends of only TEA/MDEA ester quat (and optionally water) provide improved softness without the need of other fabric softener ingredients/components.
The fabric softener composition of the present invention may also contain other quats blended therein. Other quats that may be added to the blended formulation of the present invention include, but are not limited to: di tallow dimethyl ammonium chloride, di tallow imidazolinium methyl sulfate and amido amine based methyl sulfate quats.
The present invention also provides a liquid fabric softener composition which comprises a blend of from about 15 to about 65%, by weight of the total blend, of a triethanol amine ester quat and from about 35 to about 85%, by weight of the total blend, of a methyl diethanol amine ester quat, said methyl diethanol amine ester quat having a mono alkyl ester quat level of about 10% or greater; and water.
As stated above, the present invention provides a fabric softener composition, solid and liquid, which includes at least a blend of from about 15 to about 65%, by weight of the total blend, of a triethanol amine (TEA) ester quat and from about 35 to about 85% by weight of the total blend, of a methyl diethanol amine (MDEA) ester quat, said methyl diethanol amine ester quat having a mono alkyl ester quat level of about 10% or greater. The MDEA ester quat of the present invention may be referred to herein as a xe2x80x9chigh mono alkyl MDEA ester quatxe2x80x9d or xe2x80x9cMDEA ester quat with a high content of monoesterxe2x80x9d since it contains 10% or more of a mono alkyl ester quat. The liquid fabric softener composition includes water.
More preferably, the blend of the present invention comprises from about 25 to about 50%, by weight of the total blend, of a triethanol amine ester quat and from about 50 to about 75%, by weight of the total blend, of a high mono alkyl methyl diethanol amine ester quat. Even more preferably, the blend of the present invention comprises from about 30 to about 45%, by weight of the total blend, of a triethanol amine ester quat and from about 55 to about 70%, by weight of the total blend, of a high mono alkyl methyl diethanol amine ester quat. Most preferably, the blend of the present invention comprises from about 35 to about 40%, by weight of the total blend, of a triethanol amine ester quat and from about 60 to about 65%, by weight of the total blend, of a high mono alkyl methyl diethanol amine ester quat.
As stated above, the high mono alkyl MDEA ester quat, i.e., MDEA ester quat with a high content of monoester, of the present invention contains about 10% or greater of the corresponding mono alkyl ester quat present therein. The mono alkyl ester component, i.e., monoester, is a bi-product that is typically formed during the synthesis of the MDEA ester quat. In the prior art, it is known to use MDEA ester quats that have a low level of mono alkyl ester component. In the present invention, however, the MDEA ester quat employed has a high mono alkyl ester component, i.e., monoester, that is within the range mentioned above. More preferably, the high mono alkyl MDEA ester quat of the present invention contains from about 15 to about 50% of the corresponding mono alkyl ester component. Even more preferably, the level of mono alkyl ester component present in the MDEA ester quat is from about 20 to about 35%.
The term xe2x80x9cTEA ester quatxe2x80x9d is used in the present invention to denote an ester quat having the following structural formula: 
in which each Ra is individually selected from the group consisting of straight or branched chain, optionally substituted alkyl groups having from 11 to 23 carbon atoms; Ra1 is the alkyl or aralkyl moiety of the alkylating agent, i.e., a C1-C4, preferably C1-C3, straight or branched alkyl or a C7-C10 aralkyl; ALK is an alkylene having from 2 to about 6 carbon atoms; Zxe2x88x92 is a softener compatible anion such as, for example, a halogen, CH3SO4xe2x88x92 or C2H5SO4xe2x88x92; and x+y=the mole ratio of fatty acid to triethanol amine, i.e., 1.2 to 2.5. More preferably, each Ra is individually selected from the group consisting of straight or branched chain, optionally substituted alkyl groups having from 11-21 carbon atoms; Ra1 is methlyl; ALK is an C2H4; and Zxe2x88x92 is an anion such as Clxe2x88x92, CH3SO4xe2x88x92, C2H5SO4xe2x88x92, and other like softening anions.
The TEA ester quat is prepared using conventional procedures that are well known to those skilled in the art. For example, the TEA ester quat may be prepared by reacting at least one C12-C22 fatty acid, the hydrogenation product thereof, or a mixture of such acids, with a triethanol amine, optionally in the presence of an acid catalyst, wherein the ratio of fatty acid to triethanol amine is from about 1.2-2.5. The resultant esteramine reaction product is subsequently quaternized to obtain the TEA ester quat of the present invention.
The fatty acid is preferably a C16-C22 acid containing a degree of unsaturation such that the iodine value (xe2x80x9cIVxe2x80x9d) is in the range of from about 0-150, preferably, from about 0-70, and more preferably in the range of 0-50. Preferred fatty acids include, but are not limited to: oleic, palmitic, erucic, eicosanic and mixtures thereof. Soy, tallow, partially hydrogenated tallow, palm, palm kernel, rape seed, lard, coconut, canola, safflower, corn, rice, tall oil and mixtures thereof and the like are typical sources for fatty acids which can be employed in the present invention. The fatty acids can be partially or fully hydrogenated and blends of the above-mentioned oils or other naturally occurring oils or triglycerides may be used.
Partial hydrogenation or full hydrogenation can be employed, if required, to minimize the polyunsaturate levels in order to improve the stability (e.g., odor, color, etc.) of the final product.
The molar ratio of fatty acid to triethanol amine is generally in the range of from about 1.2 to 2.5, preferably from about 1.4-2.0, and more preferably, in the range of from about 1.6-1.9. Examples of acid catalysts that may be employed in the present process include, but are not limited to: acid catalysts such as sulphonic acid, phosphorous acid, p-toluene sulphonic acid, methane sulphonic acid, oxalic acid, hypophosphorous acid or an acceptable Lewis acid in an amount of 500-3000 ppm based on the amount of fatty acid charge. A preferred acid catalyst is hypophosphorous acid. Typically, 0.02-0.2% by weight, and more preferably 0.1 to 0.15% by weight of acid catalyst, based on the weight of fatty acid may be employed in the present process.
The esterification of fatty acids with triethanol amine is carried out at a temperature of from about 170xc2x0 C.-250xc2x0 C. until the reaction product has an acid value of below 5. After the esterification, the crude product is reacted with an alkylating agent in order to obtain the quaternary ammonium product. Preferred alkylating agents include C1-C4, more preferably C1-C3, straight or branched chain alkyl halides, phosphates, carbonates, or sulfates, C7-C10 aralkyl halides, phosphates or sulfates, and mixtures thereof. Examples of preferred alkylating agents employed in the present invention include, but are not limited to: methyl chloride, benzyl chloride, diethyl sulfate, dimethyl carbonate, trimethyl phosphate, dimethyl sulfate or mixtures thereof. Choosing the type and amount of alkylating agent employed is well within the skill of one in the art.
The term xe2x80x9cMDEA ester quatxe2x80x9d is used in the present invention to denote an ester quat having the following structural formula: 
in which RB is individually selected from the group consisting of straight or branched chain, optionally substituted alkyl groups having from 11 to 23 carbon atoms; ALK is an alkylene having from 2 to about 6 carbon atoms; k= the mole ratio of fatty acid to MDEA, i.e., 1.2 to 1.7; Rc is a C1-C4, preferably a C1-C3, alkyl, or a C7-C10 aralkyl; and Zxe2x88x92 is a softener compatible anion such as a halogen, CH3SO4xe2x88x92 or C2H5SO4xe2x88x92. Preferably, RB is individually selected from the group consisting of straight or branched chain, optionally substituted alkyl groups having from 11-21 carbon atoms; ALK is C2H4; Rc is methyl; and Zxe2x88x92 is an anion such as Clxe2x88x92, CH3SO4xe2x88x92, and C2H5SO4xe2x88x92.
The MDEA ester quat is prepared using a procedure in which a high mono alkyl ester component, e.g., monoester, is obtained. For example, the MDEA ester quat may be prepared by reacting at least one C12-C22 fatty acid, the hydrogenation product thereof, or a mixture of such acids, with methyl diethanol amine optionally, in the presence of an acid catalyst, wherein the ratio of fatty acid to diethanol amine is from about 1.2-1.7. The resultant esteramine reaction product is subsequently quaternized to obtain the MDEA ester quat of the present invention.
The fatty acid is preferably a C16-C22 acid containing a degree of unsaturation such that the iodine value (xe2x80x9cIVxe2x80x9d) is in the range of from about 0-150, preferably, from about 0-70, and more preferably in the range of 0-50. Preferred fatty acids include, but are not limited to: oleic, stearic palmitic, erucic, eicosanic and mixtures thereof. Soy, tallow, partially hydrogenated tallow, palm, palm kernel, rape seed, lard, coconut, canola, safflower, corn, rice, tall oil and mixtures thereof and the like are typical sources for fatty acids which can be employed in the present invention. The fatty acids can be partially or fully hydrogenated and blends of the above-mentioned oils or other naturally occurring oils or triglycerides may be used.
Partial hydrogenation or full hydrogenation can be employed, if required, to minimize the polyunsaturate levels in order to improve the stability (e.g., odor, color, etc.) of the final product.
The molar ratio of fatty acid to diethanol amine is generally in the range of from about 1.2 to 1.7, preferably from about 1.2-1.5, and more preferably, in the range of from about 1.2-1.35. The acid catalyst that may be used in the present process includes, but is not limited to: acid catalysts such as sulphonic acid, phosphorous acid, p-toluene sulphonic acid, methane sulphonic acid, oxalic acid, hypophosphorous acid or an acceptable Lewis acid in an amount of 500-3000 ppm based on the amount of fatty acid charge. A preferred acid catalyst is hypophosphorous acid. Typically, 0.02-0.2% by weight, and more preferably 0.1 to 0.15% by weight of acid catalyst, based on the weight of fatty acid, may be employed in the present process.
The esterification of fatty acids with diethanol amine is carried out at a temperature of from about 170xc2x0 C.-250xc2x0 C. until the reaction product has an acid value of below 5. After the esterification, the crude product is reacted with an alkylating agent in order to obtain the quaternary ammonium product. Preferred alkylating agents include C1-C4, more preferably C1-C3, straight or branched chain alkyl halides, phosphates, carbonates, or sulfates, C7-C10 aralkyl halides, phosphates or sulfates, and mixtures thereof. Examples of preferred alkylating agents employed in the present invention include, but are not limited to: methyl chloride, benzyl chloride, diethyl sulfate, dimethyl carbonate, trimethyl phosphate, dimethyl sulfate or mixtures thereof. Choosing the type and amount of alkylating agent employed is well within the skill of one in the art.
Because of the synthesis employed in making the MDEA ester quat, a mono alkyl ester component, e.g., monoester, is typically present. In the present invention, the mono alkyl ester component is typically present in an amount of about 10% or greater.
As stated above, the fabric softener composition of the present invention includes a blend of at least one TEA ester quat and at least one high mono alkyl MDEA ester quat, i.e., MDEA ester quat with a high content of monoester. That is, the fabric softener composition of the present invention is a product that is obtained from blending the TEA ester quat with the high mono alkyl MDEA ester quat, i.e., MDEA ester quat with a high content of monoester. The present invention does not include a product in which an amine pre-mixture is first provided and thereafter the amine pre-mixture is esterified and quaternized.
The blending step of the present invention is carried out using procedures well known to those skilled in the art. In particular, the blending is carried out in an apparatus containing a stirrer. The individual ester quits ;ire added to the apparatus in any order and then stirring is initiated.
In accordance with the present invention, die blend comprises from about 15 to about 65%, by weight of the total blend, of a triethanol amine ester quat and from about 35 to about 85%, by weight of the total blend, of a high mono alkyl methyl diethanol amine ester quat, i.e., MDEA ester quat with a high content of monoester. More preferably, the blend of the present invention comprises from about 25 to about 50%, by weight of the total blend, of a triethanol amine ester quat and from about 50 to about 75%, by weight of the total blend, of a high mono alkyl methyl diethanol amine ester quat. Even more preferably, the blend of the present invention comprises from about 30 to about 45%, by weight of the total blend, of a triethanol amine ester quat and from about 55 to about 70%, by weight of the total blend, of a high mono alkyl methyl diethanol amine ester quat. Most preferably, the blend of the present invention comprises from about 35 to about 40%, by weight of the total blend, of a triethanol amine ester quat and from about 60 to about 65%, by weight of the total blend, of a high mono alkyl methyl diethanol amine ester quat.
The solid fabric softener blend of the present invention may be formulated into an aqueous, i.e., liquid, fabric softener, by adding water to the blended product. The amount of water added to the blended product is typically from about 250 to about 5000 ml per 100 grams of blended product. More preferably, the amount of water added is from about 900 to about 300 ml water per 100 grams of blended product.
The blended TEA/MDEA ester quat product of the present invention has a solids content, as measured by oven evaporation, of about 10 to about 30%. More preferably, the solids content of the blended product of the present invention is from about 20 to about 28%.
The blended product of the present invention may also include other quaternary ammonium compounds including di ester ammonium quaternaries, inadizolinum based quaternaries, and amido amine based quaternaries that arc well known to those skilled in the art. Examples of some optional quats that may preferably be employed in the present invention include, but are not limited to: di tallow dimethyl ammonium chloride, di tallow imidazaolium methyl sulfate, amido amine based quaternaries and the like thereof, including mixtures thereof.
The other quats may be added during or after the initial blending process. The amount of other quats that may be used in the present invention is from about 0 to about 60%, based on the total blend, with an amount of other optional quat of from about 0 to about 20% being more highly preferred.
The other quats employed in the present invention arc typically difficult to formulate into high-solids formulation. In the present invention, the blend of TEA/MDEA ester quats allows other quats to be used in a high-solids formulation.
The formulated blend of a high monoalkyl MDEA ester quat, i.e., MDEA ester quat with a high content of monoester, and a TEA ester quat provides improved softening performance that is better than that obtained with either of the individual components. In addition, the applicants have determined that even though the individual products can be formulated to 12 to 18% solids, when the two ester quats are blended together, as in the present invention, the blend may have a solids content about 25% or higher. Moreover, the inventive blend of a high mono alkyl MDEA ester quat, i.e., MDEA ester quat with a high content of monoester, and a TEA ester quat forms a stable dispersion that maintains long-term stability.
Although the stability of the fabric softening composition of the present invention is such that stabilizing cosurfactants are not required, they may nevertheless be included along with a wide variety of other optional ingredients. A non-limiting description of some of the optional ingredients that may be employed in the fabric softening composition of the present invention is provided below. These optional ingredients may be added before, or after, the initial blending process.
As mentioned above, relatively concentrated compositions of the inventive blend can be prepared that are stable, without the addition of concentration aids. However, the compositions of the present invention may require organic and/or inorganic concentration aids to go to even higher concentrations and/or to meet higher stability standards depending on the other ingredients. These concentration aids, which are typically viscosity modifiers, may be needed, or preferred, for ensuring stability under extreme conditions when particular softener active levels in relation to IV are present.
Surfactant Concentration Aids
Surfactant concentration aids typically fall into four categories:
(1) mono long chain alkyl cationic surfactants;
(2) nonionic surfactants;
(3) amine oxides; and
(4) fatty acids.
Mixtures of the aforementioned surfactant concentration aids can, of course, also be employed.
(1) Mono-long Chain Alkyl Cationic Surfactants
Preferred mono-long chain alkyl or ester based water-soluble cationic surfactants generally fall within the scope of the following general formula:
[R2N+(R)3 ]Xxe2x88x92
wherein the R2 group is C8-C22 hydrocarbon group, preferably C12-C18 alkyl group or the corresponding ester linkage interrupted group with a short chain alkylene (C1-C6) group between the ester linkage and the N, and having a similar hydrocarbon group. Each R is a C1-C6 unsubstituted or substituted alkyl (e.g., by hydroxy) or hydrogen, preferably methyl, and the counterion Xxe2x80x94 is a softener compatible anion such as, for example, chloride, bromide, methyl sulfate, etc.
The cationic surfactants, if present, are usually added to solid compositions at a level of from 0% to about 15%, preferably from about 3% to about 15%, more preferably from about 5% to about 15%. In liquid compositions they are usually employed at level of from 0% to about 15%, preferably from about 0.5% to about 10%. In general, the total amount single-long-chain cationic surfactant is added in an amount effective to obtain a stable composition. The foregoing levels represent the amount of the single-long-chain-alkyl cationic surfactant that is added to the composition of the present invention.
The long chain group R2, of the single-long-chain-alkyl cationic surfactant generally contains an alkylene group having from about 10 to about 22 carbon atoms, preferably from about 12 to about 16 carbon atoms for solid compositions, and preferably from about 12 to about 18 carbon atoms for liquid compositions.
This R2 group can be attached to the cationic nitrogen atom through a group containing one, or more, ester, amide, ether, amine, etc., preferably ester, linking groups which can be desirable for increased hydrophilicity, biodegradability, etc. Such linking groups are preferably within about three carbon atoms of the nitrogen atom. Suitable biodegradable single-long-chain alkyl cationic surfactants containing an ester linkage in the long chain are described in U.S. Pat. No. 4,840,738, which is incorporated herein by reference. If the corresponding, non-quaternary amines are used, any acid (preferable a mineral or polycarboxylic acid) which is added to keep the ester groups stable will also keep the amine protonated in the compositions and preferably during the rinse so that the amine has a cationic group. The composition is buffered (pH from about 2 to about 5, preferably from about 2 to about 4) to maintain an appropriate, effective charge density in the aqueous liquid concentrate product and upon further dilution e.g., to form a less concentrated product and/or upon addition to the rinse cycle of a laundry process.
The main function of the water-soluble cationic surfactant is to lower the viscosity and/or increase the dispersibility of the fabric softener composition of the present invention and it is not, therefore, essential that the cationic surfactant itself have substantial softening properties, although this may be the case. Also, surfactants having only a single long alkyl chain, presumably because they have greater solubility in water, can protect the fabric softener composition of the present invention from interacting with anionic surfactants and/or detergent builders that are carried over into the rinse.
Other cationic materials with ring structures such as alkyl imidazoline, imidazolimium, pyridine, and pyridinium salts having a single C12-C30 alkyl chain can also be used. Some alkyl imidazolinium salts useful in the present invention have the general formula: 
wherein Y2 is xe2x80x94C(O)xe2x80x94)xe2x80x94, xe2x80x94Oxe2x80x94(O)Cxe2x80x94, xe2x80x94C(O)xe2x80x94N(R5), or xe2x80x94N(R5)xe2x80x94C(O)xe2x80x94 in which R5 is hydrogen or a C1-C4 alkyl radical; R6 is a C1-C4 alkyl radical; R7 and R8 are each independently selected from R and R2 as defined hereinbefore for the single-long-chain cationic surfactant with only one being R2.
Some alkyl pyridinium salts useful in the present invention have the general formula: 
wherein R2 and Xxe2x88x92 are as defined above. A typical material of this type is cetyl pyridinium chloride.
(2) Nonionic Surfactantsxe2x80x94Alkoxylated Materials.
Nonionic surfactants suitable as viscosity/dispersibility modifiers include the addition products of ethylene and/or propylene oxide with fatty alcohols, fatty acids, fatty amines, etc. Any of the alkoxylated materials hereinafter described can be used as the nonionic surfactant. In general terms, the nonionics herein can be employed in solid compositions at a level of from about 5% to about 20%, preferably from about 8% to about 15, and in liquid compositions at a level of from 0% to about 5%, preferably from about 0.1% to about 5%, more preferably from about 0.2% to about 3%.
Suitable water-soluble nonionic surfactants generally fall within the scope of the following general formula:
R2xe2x80x94Yxe2x80x94(C2H4O)zxe2x80x94C2H4OH
wherein R2 for both solid and liquid compositions is selected from the group consisting of primary, secondary and branched chain alkenyl hydrocarbyl groups; and primary, secondary and branched chain alkyl- and alkenyl-substituted phenolic hydrocarbyl groups; said hydrocarbyl groups having a hydrocarbyl chain length of from about 8 to about 20, preferably from about 10 to about 18 carbon atoms. More preferably the hydrocarbyl chain length for liquid compositions is from about 16 to about 18 carbon atoms and for solid compositions from about 10 to about 14 carbon atoms. In the general formula for the ethoxylated nonionic surfactants herein, Y is typically xe2x80x94Oxe2x80x94, xe2x80x94C(O)xe2x80x94, xe2x80x94C(O)N(R)xe2x80x94, or xe2x80x94C(O)N(R)Rxe2x80x94, wherein R, when present, has the meanings given hereinbefore, and/or R can be hydrogen, and z is at least about 8, preferably at least about 10-11. Performance, and usually stability of the softener composition decrease when fewer ethoxylate groups are present.
The nonionic surfactants herein are characterized by an HLB (hydrophilic-lipophilic balance) of from about 7 to about 20, preferably from about 8 to about 15. By defining R2 and the number of ethoxylate groups, the HLB of the Surfactant is, for the most part, determined. However, it is preferred that for concentrated liquid compositions, the nonionic surfactants contain relatively long chain R2 groups and are relatively highly ethoxylated. While shorter alkyl chain surfactants having short ethoxylated groups may possess the requisite HLB, they are not as effective.
Nonionic surfactants that may be employed in the present invention include, but are not limited: in the examples, the number of ethoxyl groups in the molecule (EO) is defined by an integer.
(i) Straight-chain, Primary Alcohol Alkoxylates
The deca-, undeca-, dodeca-, tetradeca-, and pentadeca-ethoxylates of n-hexadecanol, and n-octadecanol having an HLB within the preferred range are useful as viscosity/dispersibility modifiers of the context of the present invention. Preferred examples of ethoxylated primary alcohols useful herein include, but arc not limited to: n-C18EO(10) and n-C10EO(11). The ethoxylates of mixed natural or synthetic alcohols in the xe2x80x9ctallowxe2x80x9d chain length range arc also useful herein. Specific examples of such materials include tallow alcohol-EO(11), tallow alcohol-EO(18), and tallow alcohol-EO(25).
(ii) Straight-chain, Secondary Alcohol Alkoxylates
The deca-, undeca-, dodeca-, tetradeca-, pentadeca-, octadeca-, and nonadeca-ethoxylates of 3-hexadecanol, 2-octadecanol, 4-eicosanol, and 5-eicosanol having an HLB within the preferred range arc useful viscosity/dispersibility modifiers in the context of the present invention. Examples of ethoxylated secondary alcohols useful herein as the viscosity/dispersibility modifiers of the compositions include but arc not limited to: 2-C16 EO(11); 2-C20EO(11); and 2-C16EO(14).
(iii) Alkyl Phenol Alkoxylates
As is the case of the alcohol alkoxylates, the hexa-through octadeca-ethoxylates of alkylated phenols, particularly monohydric alkylphenols, having an HLB within the preferred range are useful as the viscosity/dispersibility modifiers. The hexa-through octadeca-ethoxylates of p-tridecylphenol, m-pentadecylphenol, and the like, are useful herein. Preferred examples of ethoxylated alkylphenols useful as the viscosity/dispersibility modifiers include but are not limited to: p-tridecylphenol EO(11) and p-pentadecylphenol EO(18).
It is generally recognized by one of ordinary skill in the art that a phenyl group in the nonionic formula is the equivalent of an alkylene group containing from 2 to 4 carbon atoms. For the present purpose, nonionic surfactants containing a phenylene group arc considered to contain an equivalent number of carbon atoms calculated as the sum of the carbon atoms in the alkyl group plus about 3.3 carbon atoms for each phenylene group.
(iv) Olefinic Alkoxylates
The alkenyl alcohols, both primary and secondary, and alkenyl phenols corresponding to those disclosed hereinabove can be ethoxylated to an HLB within the range recited herein and used as the viscosity/dispersibility modifiers in the compositions of the present invention.
(v) Branched Chain Alkoxylates
Branched chain primary and secondary alcohols which are available from the well-known xe2x80x9cOXOxe2x80x9d process can be ethoxylated and employed as the viscosity/dispersibility modifiers in the present compositions.
The ethoxylated nonionic surfactants summarized hereinabove can be usefully employed in the present compositions either alone or in specific mixtures.
(3) Amine Oxides
Suitable amine oxides include, but are not limited to: those with one alkyl or hydroxyalkyl moiety of about 8 to about 28 carbon atoms, preferably from about 8 to about 16 carbon atoms, and two alkyl moieties selected from the group consisting of alkyl groups and hydroxyalkyl groups with about 1 to about 3 carbon atoms. Amine oxides, if employed, are generally present in solid compositions at a level of from 0% to about 15%, preferably from about 3% to about 15%; and in liquid compositions at a level of from 0% to about 5%, preferably from about 0.25% to about 2%. The total amount amine oxide is generally present in an amount effective to provide a stable composition.
Preferred examples of amine oxides employable in the present invention include, but are not limited to: dimethyloctylamine oxide, diethyldecylamine oxide, bis-(2-hydroxyethyl)dodecylamine oxide, dimethyl dodecylamine oxide, dipropyltetradecylamine oxide, methylethylhexadecylamine oxide, dimethyloctadecylamine oxide, di(2-hydroxyethyl)octyldecylamine oxide and coconut fatty alkyl dimethylamine oxide.
(4) Fatty Acids and/or Alkoxylated Fatty Acids
Suitable fatty acids include those containing from about 12 to about 25, preferably from about 13 to 22, more preferably from about 16 to about 20, total carbon atoms, with the fatty moiety containing from about 10 to about 22, preferably from about 10 to about 18, more preferably from about 10 to about 14 carbon atoms. Fatty acids are typically present at approximately the levels outlined above for amine oxides. Alkoxylated fatty acids prepared by reaction alkylene oxide with the aforementioned fatty acids can also be preferably employed in the compositions of the present invention.
Electrolyte Concentration Aids
Inorganic viscosity control agents that can also act like, or augment the effect of the surfactant concentration aids include: water-soluble, ionizable salts. Such salts can also optionally be incorporated into the fabric softener compositions of the present invention. A wide variety of ionizable salts can be used. Examples of suitable salts include, but are not limited to: the halides of the Group IA and IIA metals of the Periodic Table of Elements, e.g., calcium chloride, magnesium chloride, sodium chloride, potassium bromide, and lithium chloride. The amount of ionizable salts used depends on the amount of active ingredients used in the compositions. Typical levels of salts used to control the composition viscosity are from about 20 to about 20,000 ppm, preferably from about 20 to about 11,000 ppm, by weight of the composition.
Alkylene polyammonium salts can be incorporated into the composition to give viscosity control in addition to, or in place of, the water-soluble, ionizable salts described above. Additionally, these agents can act as scavengers, forming ion pairs with anionic detergent carried over from the main wash to the rinse and may improve softening performance. These agents may stabilize the viscosity over a broader range of temperature, especially at low temperatures, compared to the inorganic electrolytes. Some examples of alkylene polyammonium salts include but are not limited to 1-lysine monohydrochloride and 1,5-diammonium-2-methylpentane dihydrochloride.
Stabilizers may also be optionally employed in the compositions of the present invention. The term xe2x80x9cstabilizer,xe2x80x9d as used herein, includes antioxidants and reductive agents. These agents arc typically present at levels of from 0% to about 2%, preferably from about 0.01% to about 0.2%, more preferably from about 0.05% to about 0.1% for antioxidants and more preferably from about 0.01% to about 0.2% for reductive agents. The stabilizers provide good odor stability under long term storage conditions. Examples of antioxidants which can be employed in the compositions of the present invention include, but are not limited to: a mixture of ascorbic acid, ascorbic palmitate, and propyl gallate; a mixture of BHT (butylated hydroxytoluene), BHA (butylated hydroxyanisole), propyl gallate, and citric acid; butylated hydroxytoluene; tertiary butylhydroquinone; natural tocopherols; and butylated hydroxyanisole; long chain esters. (C8-C22) of gallic acid such as dodecyl gallate; and the like.
Examples of reductive agents include, but are not limited to; sodium borohydride, sodium bisulfite, hypophosphorous acid, and mixtures thereof.
Soil Release Agent
The fabric softener composition of the present invention may optionally contain from 0.1% to 10%, preferably from 0.2% to 5%, of a soil release agent. Preferably, the soil release agent is a polymeric soil release agent such as one which contains copolymeric blocks of terephthalate and polyethylene oxide or polypropylene oxide, cationic guar gums, and the like. U.S. Pat. No. 4,956,447, which is incorporated herein by reference, discloses some preferred soil release agents comprising cationic functionalities.
Cellulosic derivatives are also functional as soil release agents. Examples of such agents include, but are not limited to: hydroxyethers of cellulose, methyl cellulose, hydroxypropyl methylcellulose, hydroxybutyl methylcellulose, or mixtures thereof wherein said cellulosic polymer has a viscosity in a 2% aqueous solution at 20xc2x0 C. of 15 to 75,000 centipose. Other effective soil release agents arc cationic guar gums.
Bacteriocides
Examples of bacteriocides which can be employed in the compositions of the present invention include, but are not limited to: parabens such as methyl, glutaraldehyde. formaldehyde, 2-bromo-2-nitropropane-1,3-diol, and a mixture of 5-chloro-2-methyl-4-isothiazoline-3-one and 2-methyl-4-isothiazoline-3-one. Typical levels of bacteriocides used in the present compositions are about 1 ppm to about 2,000 ppm by weight of the composition, depending on the type of bacteriocide selected.
Silicones
Dimethylpolysiloxane (silicone) or modified silicone can be added to the composition of this present invention, in order to enhance the softening property and water-absorbency of the unsaturated quaternary ammonium salt of formula (I)-(III). Dimethypolysiloxane or a modified silicone, having a viscosity of 20-10000 cps at 25xc2x0 C., is preferred.
Modified silicones useful in the present invention include, for example, polyoxyethylene modified silicone and amino-modified silicone, wherein the amount of the modification is preferably less than 10%.
It is preferable that dimethylpolysiloxane or modified silicones are emulsified with a polyoxyethylene-type nonionic surfactant or a monoalkylcationic-type or dialkylcationic-type cationic surfactant prior to their use.
Other Optional Components
The present invention can include other optional components conventionally used in textile treatment compositions, for example, colorants, preservatives, optical brighteners, opacifiers, fabric conditioning agents, surfactants, stabilizers such as guar gum, anti-shrinkage agents, anti-wrinkle agents, fabric crisping agents, anti-spotting agents, fungicides, anti-corrosion agents, antifoam agents, and the like.
An optional additional softening agent of the present invention is a nonionic fabric softener material. Typically, such nonionic fabric softener materials have an HLB of from about 2 to about 9, more typically from about 3 to about 7. The foregoing nonionic fabric softener materials tend to be readily dispersed either by themselves, or when combined with other materials such as a single-long-chain alkyl cationic surfactant, the materials as set forth hereinafter, use of hotter water, and/or with more agitation. In general, the materials selected should be relatively crystalline, higher melting, (e.g., 50xc2x0 C. or greater) and relatively water-insoluble.
The level of optional nonionic softener in the solid composition is typically from about 10% to about 40%, and preferably from about 15% to about 30%. The level of optional nonionic softener in the liquid composition is typically from about 0.5% to about 10%, preferably from about 1% to about 5%. Preferred nonionic softeners are fatty acid partial esters of polyhydric alcohols, or anhydrides thereof, wherein the alcohol, or anhydride, contains from 2 to about 18, preferably from 2 to about 8, carbon atoms, and each fatty acid moiety contains from about 12 to about 30, preferably from about 16 to about 20 carbon atoms. Typically, such softeners contain from about one to about 3, preferably about 2 fatty acid groups per molecule.
The polyhydric alcohol portion of the ester can be ethylene glycol, glycerol, poly (e.g., di-, tri-, tetra, penta-, and/or hexa-) glycerol, xylitol, sucrose, erythritol, pentaerythritol, sorbitol or sorbitan. Sorbitan esters and polyglycerol monostearate are particularly preferred. The fatty acid portion of the ester is normally derived from fatty acids having from about 12 to about 30, preferably from about 16 to about 20 carbon atoms, typical examples of said fatty acids being lauric acid, myristic acid, palmitic acid, stearic acid and behenic acid.
Examples of sorbitan esters that maybe employed in the softening composition of the present invention include: sorbitan monolaurate, sorbitan monomyristate, sorbitan monopalmitate, sorbitan monobehenate, sorbitan monooleate, sorbitan dilaurate, sorbitan dimyristate, sorbitan dipalmitate, sorbitan distearate, sorbitan dibehenate, sorbitan dioleate, and mixtures thereof, and mixed tallowalkyl sorbitan mono- and di-esters. Such mixtures are readily prepared by reacting the foregoing hydroxy-substituted sorbitans, particularly the 1,4 and 1,5-sorbitans, with the corresponding acid or acid chloride in a simple esterification reaction. It is to be recognized, of course, that commercial materials prepared in this manner will comprise mixtures usually containing minor proportions of uncyclized sorbitol, fatty acids, polymers, isosorbide structures, and the like.